Conventionally, there are known substrate retaining devices that are capable of in semiconductor processing or the like, transferring a plurality of substrates from a cassette case, the cassette case storing substrates such as silicon wafers in such a manner that the substrates are arranged in their thickness direction at a predetermined pitch, to another cassette case at one time. In particular, there is a known substrate retaining device that is capable of, when transferring the substrates, changing the pitch between the substrates if such a pitch change becomes necessary in relation to the previous or following processing step (see Patent Literature 1, for example).
The substrate retaining device includes: a plurality of substrate retaining parts each including three or more claw portions configured to hold the edge of a substrate; a pitch-changing mechanism configured to change the pitch between the substrate retaining parts; steel tapes each having a bent middle portion and each having one end connected to a corresponding one of the claw portions; and drivers to which the other ends of the steel tapes are connected, the drivers being configured to make reciprocating movement in a direction from the edge toward the center of the substrate. When the pitch-changing mechanism changes the pitch between the substrate retaining parts, the straight-line distance between both ends of the steel tapes changes, accordingly. As a result, the steel tapes become warped. Even in such a case, elasticity generated by the bent portions of the steel tapes absorbs the warp of the steel tapes, and thereby substrate holding force is kept constant.